Analysis of Multi-Residue Pesticides in Cabbage with QuEChERS Extraction and Automated μSPE Clean-up Using the AOC-6000 Plus

Importance of the Topic

Monitoring pesticide residues in food is critical for public health and regulatory compliance. Gas chromatography coupled with tandem mass spectrometry is a powerful detection technique but requires efficient sample cleanup to ensure accurate quantitation.

Objectives and Study Overview

This study presents an automated workflow combining QuEChERS extraction and micro solid phase extraction cleanup using the AOC-6000 Plus autosampler to analyze multi residue pesticides in cabbage. An optional auto calibration protocol was implemented to prepare matrix matched calibration curves in situ.

Methodology and Instrumentation

• Sample extraction using European EN 15662 QuEChERS kit with acetonitrile and salt mixture, followed by centrifugation to obtain the extract
• Automated muSPE cleanup on AOC-6000 Plus with universal sorbent cartridges, including optional analyte protectants and automated calibration using a 5000 ppb stock solution
• GC MS MS analysis on Shimadzu GCMS TQ8040 NX, employing Smart Pesticides Database ver2 Method 3, SH I 5MS column and 2 uL splitless injection, with data acquisition at 50 Hz and data processing in LabSolutions Insight

Main Results and Discussion

The automated workflow delivered high consistency and effective removal of matrix interferences. Calibration linearity exceeded R2 of 0.99 for 91 percent of the 92 pesticides tested. Limits of quantitation reached as low as 0.4 ppb for 63 percent of compounds, well below the 10 ppb regulatory requirement. Method recoveries and muSPE efficiencies were within plus or minus 30 percent for all analytes and within plus or minus 20 percent for 88 percent of compounds.

Benefits and Practical Applications

• Substantial time savings and reduced manual labor through sample preparation automation
• Improved reproducibility and minimization of human error
• Fresh sample cleanup immediately before analysis enhances sensitivity and instrument robustness
• Plug and play method package lowers the technical barrier for routine laboratories

Future Trends and Potential Applications

Future developments may include extension to diverse food and environmental matrices, integration of alternative sorbents, advanced autosampler protocols for other cleanup techniques, expansion of spectral databases and AI driven data review for higher throughput and adaptability.

Conclusion

The combination of QuEChERS extraction, automated muSPE cleanup with AOC 6000 Plus and fast GC MS MS analysis on the TQ8040 NX provides a robust high throughput solution for multi residue pesticide monitoring in food. Automation and pre optimized method packages streamline workflows and ensure reliable compliance with regulatory limits.

Reference

1. Shimadzu App News M279 Study of a method for coping with matrix effects in pesticide residue analysis using GC MS MS
2. Lehotay SJ Han L Sapozhnikova Y Automated mini column solid phase extraction cleanup for high throughput analysis of chemical contaminants in foods by low pressure gas chromatography tandem mass spectrometry Chromatographia 79 17 2016 1113 1130
3. European Union legislation on maximum residue levels for pesticides in food